During the course of the operation of a railroad line, safety is an extremely important consideration, and it is especially necessary to provide and maintain the integrity of the actual rails and track area. As a result, a variety of devices and maintenance equipment have been developed to improve the efficiency of track maintenance procedures. For example, automatic snow removal and track laying equipment are routinely used to ensure operation of a rail line with only minimal inconvenience and interruption.
A particular problem that has been addressed in a variety of ways is the maintenance and replacement of the support ties (i.e., "railroad ties") over which the actual track rails run. Typically, a plurality of parallel track rails are supported by elongated wood or cement members (i.e., support ties) of rectangular cross section which are spaced beneath the rails perpendicular to the direction of rail travel. These support ties are usually embedded in a track bed of crushed stone or gravel. Often, because of the elements or through extended use, the support ties become damaged, warped or unstable. Accordingly, it is necessary to routinely extract and replace damaged support ties to insure the continued integrity of the rail line and overlying track rails. It is, of course, desirable to extract and replace damaged support ties quickly and efficiently without having to remove a length of actual track rail thereby rendering a particular track line inoperative for a period time.
Accordingly, various devices have been adopted to remove and replace support ties by securely gripping and then pulling a particular tie from beneath the track rails supported thereby. Many of these devices are heavy or mechanically bulky and require a maintenance locomotive or other similar railroad equipment for positioning and operation. These types of devices, of course, cause a particular track to be rendered inoperative since the track is effectively "blocked" to all other traffic during the course of maintenance operations unless a "side track" is close by. "Blocking" a length of track for any significant length of time is particularly undesirable in areas where no "side tracks" are conveniently located; e.g., in rural areas or between widely spaced destinations or in desolate and unpopulated areas. Thus, the "blocking" of an isolated line may result in total suspension of all traffic over such line and, in some cases, emergency conditions requiring re-routing of other, non-maintenance trains.
This problem has led to the development of various portable support tie extracting and replacing devices which may be transported to a particular track site either by maintenance train or by truck and placed upon a length of track by a work crew. These devices are generally adapted to be lifted and positioned through the use of conveniently located handles on the device. The devices typically comprise a light-weight skeletal support frame with wheels adapted to span the distance between the rails much like a locomotive or other track maintenance machine. Typically, mounted on the support frame are a series of pistons and cylinders used to secure a gripping mechanism to a particular tie to be removed and to provide a lateral or horizontal force to extract or insert the tie beneath the track rails. The prior art includes a number of similar patented devices which are described and operate in an almost identical manner; e.g., German Patent No. G-78 21 516.4 (Pierobon); Italian Patent No. 34.839 B/77 (Pierobon) and French Patent No. 7821163 (Pierobon). Each of these foreign patents describe and claim a portable device for replacing support ties using a series of pistons and cylinders.
Although the referenced patented devices and similar devices are relatively effective and efficient, numerous problems have been identified attendant to their continued use. In particular, the devices, primarily used in Europe, do not have the flexibility to be safely adapted and used with variable width track or track of special configuration. For example, depending on geographic location, track rails may be nine-inch or a six-inch gauge (or width) requiring a portable extractor to be adaptable to the variable widths. Also, safety considerations inherent to a particular track area (e.g., those attendant to double tracks on bridge crossings or to the merging of multiple tracks called "frog" connections) require flexible and adaptable means to secure the device to these various different track configurations during operation. The prior art does not have this flexibility either. As will be appreciated by one of ordinary skill in the art, the force generated by such devices is rather large (18,000 to 20,000 pounds) to enable the ties to be pulled from beneath the track and through the track bed without rail removal. Accordingly, it is essential that the replacement device be securely affixed to the top of the track rail during operation which is normally done through spacers (i.e., three-sided clamps attached to the device frame which fit over the rail width) to ensure safe operation. The known prior art does not have such securing means adaptable to meet all of these conditions; i.e., variable track width and different track configurations. This, of course, limits use of the prior art devices to specific track conditions.
Moreover, the devices described in the known prior art also fail to address other undesirable, unsafe conditions. For instance, the hoses connecting the hydraulic control systems and fluid sources to the various cylinders described in the prior art are often exposed unnecessarily. In particular, the devices require that certain hoses be capable of extending a distance equal to the stroke of certain pistons and cylinders. This results in the hoses being extraordinarily long and therefore susceptible to rupture or damage during and after operation.
In addition, although the prior art devices are apparently portable, none are equipped with appropriate safety release valves or other means for quickly removing the grippers or the secured frame from the track if the engine powering the piston seizes or malfunctions during operation. Accordingly, in the event of a breakdown, it is often the case that the prior art devices, although portable, effectively "block" the track much like bulky or locomotive powered devices until their engine can be repaired.
Accordingly, the invention solves these problems by providing a means for securing the device to various types of track or track configurations and further, providing a hose reel to automatically coil any excess hose, as well as a safety release valve and reservoir for releasing pressure in the cylinders in the event of malfunction or emergency, independent of engine operation.